In recent years, electronic devices capable of handling a digitalized video or audio such as personal computers and smartphones have become widespread. An electronic device of this type generally incorporates therein a data communication function, and is capable of transmitting/receiving audio-visual (AV) content between itself and other electronic devices.
On the other hand, among the AV content items, there are quite a number of content items the copyright of which requires protection by, for example, limiting duplication. Accordingly, various contrivances configured to transmit/receive AV content items between a plurality of electronic devices while effecting copyright protection have hitherto been proposed.
As a system configured to protect a visual copyright, for example, the high-bandwidth digital content protection system (HDCP) is known. Further, as a system configured to protect an audio copyright, for example, the serial copy management system (SCMS) is known. The HDCP is a system involving encryption of data to be copyright-protected, and the SCMS is a system involving no encryption of data to be copyright-protected. Accordingly, regarding the video and audio included in one AV content item, although the object of copyright protection is common to both of them, a case where they differ from each other in degree of countermeasure to be required as copyright protection, such as a case where encryption is required of one of them, whereas so far as encryption is not required of the other one is conceivable.
Incidentally, heretofore, only one copyright protection system has been adopted to transmit one AV content item to one transmission path, and adopting a plurality of copyright protection systems to transmit one AV content item to one transmission path has not totally been conceived. Accordingly, for example, it has been necessary to subject even the audio of which so far as encryption is not required to encryption to be required of only the video. In such a case, however, in the electronic device on each of both the transmission side and reception side of the AV content, a useless increase in cost resulting from incorporating therein a module (which is originally unnecessary) configured to encrypt/decrypt the audio is brought about.